Structure-Activity relationships have been adapted to aid in selecting compounds for large-scale screening in mouse lymphocytic leukemia (P388). Molecular fragment statistics from compounds tested in P388 are used to estimate antitumor activity and novelty. These estimates are examined by a medicinal chemist along with the structures of over 30,000 potential acquisitions per year to decide which compounds to screen. Results from P388 on about 30,000 compounds that have been through this system indicate that the estimates are useful. This year a model for therapeutic index was installed and work was begun on estimates for activity with regard to physical parameters. A more comprehensive model included data from L1210 leukemia and B16 melanoma. In addition, these methods have yielded an automated literature surveillance project.